Composition comprising vinyl carbazole, inorganic peroxide, substituted borazole, cellulose nitrate and aminoplast resin



United States Patent O COMPOSITION COMPRISING VINYL CARBAZOLE,

INORGANIC PEROXIDE, SUBSTITUTED BOR- AZOLE, CELLULOSE NITRATE AND AMINO-PLAST RESIN Stephen J. Groszos, Cincinnati, Ohio, and Stanley F.

Staiiej, Stamford, Conn., assignors to American Cyanamid Company, NewYork, N.Y., a corporation of Maine No Drawing. Original application Mar.25, 1957, Ser. No. 647,938. Divided and this application June 24, 1958,Ser. No. 744,077

10 Claims. (Cl. 260-15) This invention relates to certain new and usefulmoldable and molded compositions, and more particularly to suchcompositions comprising vinyl carbazole, an inorganic peroxide, asubstituted borazole, cellulose nitrate and an aminoplast resin.

The substituted borazoles used in practicing this invention areB-trimethyl-N-triphenylborazole and B-triphenyl- N trimethylborazole.B-trimethyl-N-triphenylborazole (B,B',B" trimethyl N,N',Ntriphenylborazole) has the formula (I) CH3 iB-triphenyl-N-trimethylborazole (B,B,B"-triphenyl-N,N,N"-trimethylborazole) has the formula In the above formulas, as Wellas elsewhere herein, the symbol means C H The substituted borazolesemployed in practicing this invention are unique in that they contain nocarbon-tocarbon bond in an aliphatic chain, and hence constitutesubstituted borazoles which are characterized by improved stability toheat and oxidation as compared with similar borazoles containing ahigher number of carbon atoms in alkyl substituents. As will be readilyappreciated by those skilled in the art, this is a matter ofconsiderable practical importance in many applications or uses ofchemical compounds including boron compounds such as the borazoles.

B-trimethyl-N-triphenylborazole and B-triphenyl-N-trimethylborazole arenormally solids. They are useful, for instance, as components offlame-resisting compositions; as plasticizers; as fuel additives; asscintillation counters; as the active ingredient in insecticides,bactericides, germicides, fungicides, pesticides and the like; as achemical intermediate for use in the preparation of other compounds; asa component of arc-extinguishing tubes, and especially of surfaces thatare exposed to the action of the arc. Other uses include: as rocketfuels or as components of such fuels; as polymer additives to impartneutron-absorbing properties to the polymer to which it is added and toimprove the thermal stability of the polymer; as heat-exchange media oras modifiers of such media whereby they can be used at highertemperatures; as petroleum additives which are hydrolytically stable,(e.g., viscosity-index improvers, lubricants and greases forhigh-temperature applications, cetane improvers, ignition promoters,anti-knock agents, preventives of pre-ignition, etc.); and in making newtypes of dyes and pigments.

In any of the aforementioned and other applications or uses, one canemploy B-trimethyl-N-triphenyl-borazole alone orB-triphenyl-N-trimethylborazole alone or a mixture ofB-trimethyl-N-triphenylborazole and B-triphenyl- N-trimethylborazole inany proportions. They can be used in conjunction with any of theconventional components of flame-resisting compositions, plasticizers,insecticides, bactericides, germicides, fungicides, pesticides, andother compositions hereinbefore mentioned by way of illustrating thefields of utility, generically and specifically, of the substitutedborazoles of this invention.

The compounds of this invention can be prepared by various methods,including those which are broadly and specifically disclosed and claimedin our copending ap plications, Serial No. 647,934, now US. Patent2,892,869, and Serial No. 647,935, filed March 25, 1957. ApplicationSerial No. 647,934 has now matured into Patent No. 2,892,869, dated June30, 1959'.

In order that those skilled in the art may better understand how thepresent invention can be carried into effect, the following examples aregiven by way of illustration and not by way of limitation.

EXAMPLE 1 Preparation of B-trimethyl-N-triphenylborazole using methyllithium Methyl lithium is prepared from 0.05 mole of methyl iodide and0.1 mole lithium in ml. of hexane. A suspension of 0.015 mole ofB-trichloro-N-triphenylborazole in 100 ml. of anhydrous ethyl other isadded to the methyl lithium solution at about 0 C. over a 20-minuteperiod. After refluxing the reaction mixture for one hour, and thencooling, a saturated solution of ammonium chloride is added until theorganic solution becomes clear. The insoluble inorganic salts areseparated by filtration, and the organic solution, after drying overanhydrous magnesium sulfate, is evaporated to dryness, leaving a nearlycolorless, crystalline solid comprising B-trimethyl-N-triphenylborazole. Recrystallization from an ethermethanol mixtureyields colorless, crystalline material of M.P. 267-269 C.

Instead of using B-tiiohloro-N-triphenylborazole as described above, onecan use an equivalent amount of B- tribromo-N-triphenylborazole.

EXAMPLE 2 Preparation of B-trz'methyl-N-triphenylborazole using methylmagnesium iodide Methyl magnesium iodide is prepared from magnesium(3.54 g.; 0.146 g. atom) and methyl iodide (22.9 g.; 0.146 mole) inanhydrous diethyl ether ml.). The resulting solution is added dropwiseover a 30-minute period to a suspension of 0.0364 mole B-trichlordN-triphenylborazole in 100 ml. other at 0-30 C. After refluxing thereaction mixture for 1 /2 hours, the cooled solution is titrated with asaturated aqueous solution of ammonium chloride to the point at whichthe magnesium salts separate from the clear, colorless ether layer. Theether solution is separated from the insoluble salts, which are washedseveral times with small quantities of fresh ether. The combined ethersolution and washings are filtered through anhydrous sodium sulfate, andthe dry ether solution is then concentrated until the product begins toseparate from solution. After cooling to room Analysis C H N nCalculated for CMHZNaBa, percent e Found, percent Instead of usingmethyl magnesium iodide as the Grignard reagent as described above, onecan use an equivalent amount of methyl magnesium chloride.

EXAMPLE 3 A. Preparation of B-trichloro-N-trlime'thylbora'zole A glasstube (1% 0.13., about 2.5 ft. long), provided with a thermocouple and aninlet for simultaneous introduction of BCl and an inert gas (helium ornitrogen) whose flow rates are measured by flowmeters, is packed at theinlet end with an intimate mixture of 15 g. of methylamine hydrochlorideand asbestos previously dried for about 16 hours in an oven at 110 C.The exit end of the tube is attached in series to a Dry-Ice trap and abubble counter. After the reactor Zone has been heated to approximately190 C., helium and boron triehloride are introduced simultaneously.After, 1.5 hours the CH NH .HCl on the asbestos appears wet, indicatingthat a reaction is taking place. After two hours, a White crystallinesolid begins to sublime to the cooler portion of the tube. The flow ofB01 is discontinued after 4.5 hours, and the crystalline solid is causedto sublime to the exit end of the tube by maintaining the flow of heliumand moving the furnace along the tube. At the end of this operation, theasbestos still contains, admixed with it, a considerable amount ofsolid. The re-heating and re-sublimation process in a stream of heliumis continued until no more crystalline material remains in the reactorzone. During this process, which requires five hours, HCl is beingevolved. Elementary analysis of the product indicates the followingcomposition: C, 14.32; H, 4.09; N, 16.31; Cl, 57.69; analysis calculatedfor a mixture of 60% B-trichloro-N-trimethylborazole, (ClB=NCH and 40%CH NHBCl C, 13.87; H, 3.80; N, 16.17; Cl, 53.82. Similarly, with theexception of analysis for chlorine, the analytical figures are in goodagreement for a mixture of 70% B-trichloro-N- trimethylborazole and 30%CH NHBCl Reheating this material at about 285 C. in a stream of nitrogenleaves a residue, the analytical values of which are in fair agreementwith those calculated for the desired product,B-trichloro-N-trimethylborazole.

Anzlysis C H Calculated for C H NaCl Be, percent Found, percent Insubsequent runs using a charge of 30 g. of

CH NH .HCl

B. Preparation of B-triphenyl-N-trimethylborazole The Grignard reagent,phenyl magnesium bromide, is prepared from 4.93 g. (0.2 mole) ofmagnesium turnings and 31.5 g. (0.2 mole) of bromob'enz'ene in 200 ml.of

anhydrous ether. A suspension of 5.0 g. of crude B-trichloro-N-trimethylborazole (obtained as described under A) in 60 ml.of anhydrous diethyl ether is added with stirring at room temperatureover a 15-minute period to the Grignard solution. Heat is evolved, andgradually a finely divided crystalline solid separates from the reactionmixture. Stirring is continued at room temperature for 30 minuteslonger, and then the mixture is refluxed for about 16 hours. (The amountof solid appears to increase after the first 10 minutes of refluxing.)After cooling the reaction mass to room temperature and allowing thesolids to settle, the supernatant liquid is removed by filtering througha filter stick to another flask by means of positive N pressure andreduced pressure. The crystalline residue is washed with fresh portionsof dry diethyl ether, and the washings are removed in the same manner aswas the original supernatant layer. The crystalline material is finallycollected by suspending it in a small amount of ether and filteringrapidly in the conventional manner. After drying in a vacuum desiccator,5.1 g. of crude product comprising B-triphenyl-N-trimethylborazole isobtained; M.P. 277281 C. (dec.). Recrystallization from benzene-hexanefurnishes 2.92 g. of product, M.P. 270 C. (dec.), and a second crop of0.74 g., M.P. 270 C. (dec.). Yield: 69% of the theoretical. Theanalytical sample, obtained from benzenehexane, has a melting point of270 C. (dec.).

Analysis 0 H N B Calculated for CnHmNgBs, pereent 71.88 6.89 11.97 9.25Found, percent 71. 86 6. 87 11. 54 8. 81

The original ether solution and washings from which theB-triphenyl-N-trimethylborazole is isolated, are treated with a 10%aqueous HCl solution to decompose any unreacted Grignard reagent and/orcomplexes thereof. The ether layer is washed with water and thenextracted with three 25-ml. portions of 10% aqueous NaOH solution. Thebasic aqueous layer is acidified with 10% aqueous H solution. Theresulting milky solution containing an immiscible, viscous, brown oil isextracted with ether, and the ether layer is washed with water untilneutral to litmus. Without drying, the ether soluion is evaporated to abrown, semi-solid mass which is recrystallized from water (after priortreatment with decolorizing carbon), giving 1.06 g. of phenylboronicacid.

The ether layer that remains after extraction with base (10% aqueousNaOH solution) to remove phenylboronic acid is washed with 10% aqueousHCl solution and with water until neutral to litmus. After drying overanhydrous Na SO the yellow other solution is evaporated to a reddish,mobile liquid that gives only a weak flame test for boron. A solution ofthis residue in benzene containing ethanolamine is refluxed for 12hours. From this reaction no aminoe'thyl diphenylborinite is isolated.

EXAMPLE 4 Preparation of B-triphenyl-N-trimethylborazole by reactionbetween phenylboron dichloridle and methylamine This example illustratesanother method of preparing B-triphenyl-N-trimethylborazole. Thereaction is illustrated by the following equation:

I Fe and thre'e-tenths 4.3 g. (0.02711m'ole) uaol is dissolved in 50 ml.of dry benzene and charged to a three-necked flask. The flask is fittedwith a mechanical stirrer, nitrogen and methylamine gas-inlet tubes, anda drying tube filled with potassium hydroxide.

Dry methylamine is introduced slowly to the reaction mixture at 20 C.over a period of two hours. The mixture is heated to boiling andgravity-filtered to remove the CH NH C1 formed in the reaction. The CHNH Cl is washed with three l0-ml. portions of hot benzene and thewashings added to the filtrate.

The light-amber filtrate is concentrated to about 30 ml. and n-hexaneadded until the solution becomes slightly turbid. Upon cooling, thissolution fails to yield crystals. Upon seeding, however, a precipitateof fine White needles is obtained. Yield: 2.6 grams, which correspondsto 84% of the theoretical. The melting point of these crystals uponrecrystallization is 267 268 C.

The compound is identified by infra-red as B-tn'phenyl-N-trimethylborazole.

The method described in this example with reference to the preparationof B-triphenyl-N-trimethylborazole is operative in making otherB-triphenyl-N-tri-(organo)- borazoles, more particularlyB-triphenyl-N-tri-(hydrocarbon)borazoles. For instance,B-triphenyl-N-triphenylborazole is similarly made by effecting reactionbetween phenylboron dichloride and aniline in the ratio of 3 moles ofthe former to 9 moles of the latter. The aniline dissolved in, forexample, dry benzene, is added to the stirred solution of phenylborondichloride in dry benzene at 0-30 C., and theB-triphenyl-N-triphenylborazole that forms is isolated from the reactionmass.

EXAMPLE This example illustrates the use of the aforementionedsubstituted borazoles in making the compositions of the presentinvention. More particularly, it shows the preparation of a compositionthat can be employed in making an insulating structure, especiallyadapted for use in cer tain types of electric-circuit interrupters,which structure is disposed adjacent and in confining relationship to anare formed upon opening the circuit.

A vinyl compound represented by the general formula CH =CHR wherein Rrepresents a condensed cyclic system with nitrogen united to thenucleus, and specifically fibrous vinyl carbazole, is ground (withoutdestroying its fibrous structure) with from about 1% to 10%(specifically about 5%) by weight thereof of a substance capable ofemitting oxygen in the heat of the arc. Examples of such oxygenemittingsubstances which are suitable for use are inorganic peroxides, e.g.,peroxides of magnesium, barium, calcium and the like. There is alsoground with the fibrous vinyl carbazole from about 5% to (specificallyabout 7.5%) by weight thereof of B-triphenyl-N- trimethylborazole, andabout 5% to 15% (specifically about 7.5%) by Weight thereof of anorganic compound containing nitrogen and capable of evolving anarc-extinguishing gas or gases with an explosive effect under the heatof the arc. An example of such an organic compound is cellulose nitratehaving a low nitrogen content (about 10.5% to 11.5%), which materialalso is known as pyroxylin.

A sufficient amount of an aminoplast, e.g., a ureaformaldehyde resin, atmelamine-formaldehyde resin, a urea-melamine-formaldehyde resin, etc.,is incorporated into the mass to form a composition adapted to beshaped, for instance by molding, extrusion or other suitable means. Theaminoplast may constitute, for instance, between about 40% and about 75%by weight of the composition. The molding or extruding temperatures arekept as low as possible in order to prevent decomposition of theexplosive material.

In the above-described composition the fibrous vinyl carbazole serves asa rigid carrier of the organic nitrogencontaining compound that iscapable of evolving an arcextinguishing gas with an explosive effectunder the heat of the arc and by which cellulose nitrate specifically ismeant. The B-triphenyl-N-trimethyl-borazole serves to modify and tocontrol the explosive effect of the said organic compound while at thesame time emitting arcextinguishing gases; the aminoplast acts as abinding agent; and the oxygen-emitting substance provides oxygen foroxidizing into carbon dioxide any carbon that may be formed during thegasifying process.

Instead of B-triphenyl-N-trimethylborazole in the composition describedabove, one can use B-trirnethyl-N-triphenylborazole, or a mixture ofB-triphenyl-N-trimethylborazole and B-trimethyl-N-ttiphenylborazole inany proportions.

This application is a division of our copending application Serial No.647,938, filed March 25, 1957, now abandoned in favor of our copendingapplication Serial No. 748,822, filed July 16, 1958, as acontinuation-inpart of said application Serial No. 647,938.

We claim:

1. A moldable composition comprising (1) fibrous vinyl carbazole, saidvinyl carbazole being adapted to serve as a rigid carrier of an organicnitrogen-containing compound that is capable of evolving anarc-extinguishing gas with an explosive effect under the heat of an arcformed upon opening the circuit of an electric-circuit interrupter; (2)from about 1% to about 10%, by weight of said carbazole, of an inorganicperoxide selected from the group consisting of the peroxides ofmagnesium, barium and calcium; (3) from about 5% to about 15 by weightof said carbazole, of a substituted borazole selected from the classconsisting of B-trimethyl-N-triphenylborazole,B-triphenyl-N-trimethyl-borazole, and mixtures thereof; (4) from about5% to about 15 by weight of said carbazole, of cellulose nitrate havinga nitrogen content of about 10.5% to 11.5%, said cellulose nitrate beingcapable of evolving an arc-extinguishing, gaseous material with anexplosive effect under the heat of the aforesaid arc; and (5) anaminoplast resin in an amount corresponding to from about 40% to about75 by weight of the moldable composition, said aminoplast resin beingselected from the class consisting of ureaformaldehyde resins,melamine-formaldehyde resins and urea-melamine-formaldehyde resins.

2. A moldable composition as in claim 1 wherein the substituted borazoleof (3) is B-trimethyl-N-triphenylborazole.

3. A moldable composition as in claim 1 wherein the substituted borazoleof (3) is B-triphenyl-N-trimethylborazole.

4. A moldable composition as in claim 1 wherein the substituted borazoleof (3) is a mixture of B-trimethyl- N-tr-iphenylborazole andB-t1iphenyl-N-trimethylborazole.

5. A moldable composition as in claim 1 wherein the inorganic peroxideof (2) constitutes about 5% by weight of the fibrous vinyl carbazole of(1).

6. A moldable composition as in claim 1 wherein the substituted borazoleof (3) constitutes about 7.5% by weight of the fibrous vinyl carbazoleof (l).

7. A moldable composition as in claim 1 wherein the cellulose nitrate of(4) constitutes about 7.5% by weight of the fibrous vinyl carbazole of(1).

8. A product comprising the molded composition of claim 1.

9. A moldable composition comprising (1) fibrous vinyl carbazole; (2)from about 1% to 10%, by weight of the said carbazole, of an inorganicperoxide selected from the class consisting of magnesium peroxide,barium peroxide and calcium peroxide; (3) from about 5% to 15%, byWeight of the said carbazole, of B-triphenyl- N-trimethylborazole; (4)from about 5% to 15%, by Weight of the said carbazole, of cellulosenitrate having a. nitrogen content of from about 10.5 to 11.5%; and

(5) an aminoplast resin in an amount corresponding to References Citedin the file of this patent from about 40% toabout 75% by Welglln of lrlblda- UNITED STATES PATENTS ble compositiomsald amlnoplastresm beingselected from 2,367,275 Haney et aL Jan 16, 1945 the class consisting ofurea-formaldehyde resms, melak I 2,821,463 Scott et al. Jan. 28, 1958mine-formaldehyde resms and urca-melamlne-formalde- 5 hyde resins. OTHERREFERENCES 10. A product comprising the molded composition of Royals:Advanced Organic Chemistry, published by claim 9. Prentice-Hall, Inc.,March 1954, page 533.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 2 952645 September 13 196O StephenJa Groszos et ale It is hereby certifiedthat error appears in the printed specification of the above numberedpatent requiring correction and that the said Letters Patent should readas corrected below.

Column 2, line 22, strike out "now US, Patent 2 892 869 column 3,,second table, under the heading "n" last 11116,, for "18,79" read 17079column I line 44, for "soluion" read solution same column 4, formula IIIthe right-hand portion should read as shown below instead of as 1n thepatent:

Signed and sealed this 4th day of April 1961.

(SEAL) Attest: ERNEST W. SWIDER X XX1X ARTHUR w. CROCKER AttestingOfficer A ting Commissioner of Patents UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent Noe 2 952 645 September 13 1960StephenJa Groszos et alt.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction and that the saidLetters .Patent should read as corrected below.

Column 2, line 22. strike out "now US. Patent 2 892 869 column 3, secondtable, under the heading "n" last line for "18579" read 17.19 column 4line 44, for "soluion" read solution same column 4, formula III therighthand portion should read as shown below instead of as in thepatent:

Signed and sealed this 4th day of April 1961.

(SEAL) Attest: ERNEST W. SWIDER XXXIK ARTHUR W. CROCKER AttestingOfiicer A ti g Commissioner of Patents

1. A MOLDABLE COMPOSITION COMPRISING (1) FIBROUS VINYL CARBAZOLE, SAIDVINYL CARBAZOLE BEING ADAPTED TO SERVE AS A RIGID CARRIER OF AN ORGANICNITROGEN-CONTAINING COMPOUND THAT IS CAPABLE OF EVOLVING ANARC-EXTINGUISHING GAS WITH AN EXPLOSIVE EFFECT UNDER THE HEAT OF AN ARCFORMED UPON OPENING THE CIRCUIT OF AN ELECTRIC-CIRCUIT INTERRUPTER, (2)FROM ABOUT 1% TO ABOUT 10*, BY WEIGHT OF SAID CARBAZOLE, OF AN INORGANICPEROXIDE SELECTED FROM THE GROUP CONSISTING OF THE PEROXIDES OFMAGNESIUM, BARIUM AND CALCIUM, (3) FROM ABOUT 5% TO ABOUT 15%, BY WEIGHTOF SAID CARBAZOLE, OF A SUBSTITUTED BORAZOLE SELECTED FROM THE CLASSCONSISTING OF B-TRIMETHYL-N-TRIPHENYLBORAZOLE,B-TRIPHENYL-N-TRIMETHYL-BORAZOLE, AND MIXTURES THEREOF, (4) FROM ABOUT5% TO ABOUT 15%, BY WEIGHT OF SAID CARBAZOLE, OF CELLULOSE NITRATEHAVING A NITROGEN CONTENT OF ABOUT 10.5% TO 11.5%, SAID CELLULOSENITRATE BEING CAPABLE OF EVOLVING AND ARC-EXTINGUISHING, GASEOUSMATERIAL WITH AN EXPLOSIVE EFFECT UNDER THE HEAT OF THE AFORESAID ARC,AND (5) AN AMINOPLAST RESIN IN AN AMOUNT CORRESPONDING TO FORM ABOUT 40%TO ABOUT 45% BY WEIGHT OF THE MOLDABLE COMPOSITION, SAID AMINOPLASTRESIN BEING SELECTED FROM THE CLASS CONSISTING OF UREAFORMALDEHYDERESINS, MELAMINE-FORMALDEHYDE RESINS AND UREA-MELAMINE-FORMALDEHYDERESINS.